Controlling the breakup of spiral waves in an excitable medium by applying time-delay feedback signals

The spiral-wave breakup to turbulence in an excitable medium, starting from the spiral-wave center via Doppler instability, is controlled by modulating a local region around the spiral-wave center. The modulation signal is extracted from the controlled region with a certain time delay. By injecting a feedback signal with very low intensity into a very small space area, we can successfully stabilize the spiral wave and prevent breakup to turbulence.